1. Field of the Invention
The present invention generally relates to a coordinate input apparatus for use in operating a cursor and a window on a monitor screen.
2. Description of Related Art
A mouse and a track ball are conventionally known as pointing devices for use on computers. Recently, a pointing device called a pad, a touch pad, or a track pad is also available. The pad is embedded in a note-size personal computer or externally attached to a desktop computer. Unlike the mouse, the pad need not be moved around on desktop for a pointing operation, thereby contributing to desktop space saving.
To move a cursor (also called a pointer) on the monitor screen by use of the touch pad, the user may only touch the planar operating surface of several centimeters square of pad with the finger and slide it on the pad. Like the mouse, the touch pad is arranged with the left and right buttons. In addition to use of these buttons, the user can tap an operating surface with the finger, like clicking the left button of the mouse, to perform various pointing operations such as selecting or moving an object displayed on the screen.
The tapping operation allows the user, in addition to the above-mentioned click operation, to perform a double-click operation (for use in starting an application program for example) and a drag operation (a displayed object is dragged while the left button of the mouse is kept pressed to a desired position) with a single finger.
Thus, the touch pad performs, when its operating surface is operated by the user finger, the substantially the same functions as the cursor movement and the left-button click operation of the mouse. The pad is installed on the bottom surface of the keyboard of a note-type personal computer. When the user touches the operating surface of the pad through the opening, the coordinate positional information about the point of the touch is sent to the computer.
A coordinate information analyzing block transforms the coordinate positional information received from the touch pad into coordinate values on the display device. In other words, the coordinate information analyzing block performs a coordinate system transforming operation from an input-side coordinate system to a display-side coordinate system. The input-side coordinate system is defined by maximum coordinate values (Xmax, Ymax) and minimum coordinate values (Xmin, Ymin) in the coordinate positional information on a two-dimensional plane to be inputted.
However, these maximum and minimum coordinate values differ between computers depending on the touch pad installation position in the opening. To be more specific, as shown in FIGS. 6A and 6B, the installation position relative to opening K of product B is shifted by xe2x80x9cxcex94Xxe2x80x9d for example in lateral direction (X-axis) relative to the installation position in opening K of product A. FIG. 6A is a top view illustrating superimposition of opening K of case P on touch pad T. FIG. 6B is a cross section of FIG. 6A along line 6B-6B.
Likewise, the installation position of touch pad T may be shifted by xe2x80x9cxcex94Yxe2x80x9d in vertical direction (Y-axis). Further, the installation position of touch pad T may be shifted both by xe2x80x9cxcex94Xxe2x80x9d in lateral direction and xe2x80x9cxcex94Yxe2x80x9d in vertical direction relative to the opening. Consequently, an effective area defined by the maximum coordinate values (Xmax, Ymax) and the minimum coordinate values (Xmin, Ymin) may not be fully utilized for coordinate input.
Thus, the installation position of touch pad T slightly differs from product to product. The degree and direction of the shift cannot be known until the fabrication of products is completed. Therefore, the coordinate system must be individually set to each product or restricted to the installation on a predetermined position in which a smaller effective area is provided to preclude coordinate input errors.
It is therefore an object of the present invention to provide a coordinate input apparatus that, if the input coordinate system differs between computer products, corrects the shift of the input coordinate system relative to the opening of each computer product.
In carrying out the invention and according to one aspect thereof, there is provided a coordinate input apparatus comprising: a coordinate detector installed on a case so as to be exposed through a window provided on the case, the coordinate detector being provided with an operating surface having a predetermined size that is operated with a coordinate indicator, a position indicated by the coordinate indicator on the operating surface being outputted as coordinate data about two-dimensional coordinates; a storage for storing range coordinate data about two-dimensional coordinates indicative of a rectangular coordinate input range in which a coordinate input operation is performed by the coordinate indicator on the operating surface; a data analyzing block for changing the range coordinate data according to the coordinate data inputted by the coordinate indicator; a data correcting block for transforming, based on the range coordinate data, the coordinate data into display coordinate data corresponding to coordinates on a display screen of an image display device; and a display control block for displaying the display coordinate data to the display screen of the image display device.
Thus, the range coordinate data for defining the rectangular coordinate input range is rewritten by the coordinate data indicated by the coordinate indicator. Consequently, the rectangular coordinate input range of any coordinate input apparatus can be always adapted to the operating surface exposed through the window. This eliminates the shift of the rectangular coordinate input range on the operating surface between different coordinate input apparatuses.
In carrying out the invention and according to another aspect thereof, there is provided a coordinate input apparatus wherein the range coordinate data is composed of minimum coordinate data and maximum coordinate data indicative of the rectangular coordinate input range.
Consequently, the rectangular coordinate input range can be defined by two points of the maximum coordinate data and the minimum coordinate data.
In carrying out the invention and according to still another aspect thereof, there is provided a coordinate input apparatus wherein, if the coordinate data is smaller than the minimum coordinate data, the data analyzing block replaces the coordinate data with the range coordinate data and, if the coordinate data is larger than the maximum coordinate data, the data analyzing means replaces the coordinate data with the range coordinate data.
Consequently, the rectangular coordinate input range of any coordinate input apparatus can be always adapted to the operating surface exposed through the window. This eliminates the shift of the rectangular coordinate input range on the operating surface between different coordinate input apparatuses.
In carrying out the invention and according to yet another aspect thereof, there is provided a coordinate-input apparatus wherein the rectangular coordinate input range is set inside a frame of the window.
Consequently, the rectangular coordinate input range can be expanded up to the inner circumference of the frame of the window. Therefore, even if there occurs a shift between the window of the case of the coordinate input apparatus and the installation of the operating surface, operating of the operating surface by the user with the coordinate indicator converges the rectangular coordinate input range to the operating surface inside the window, thereby eliminating the variations in rectangular coordinate input range between different coordinate input apparatuses.